Project Summary/Abstract Overall The overall goal of this Program Project Grant is to develop improved curative therapies for patients with hematological malignancies focusing primarily on adoptive cell therapy and hematopoietic cell transplantation (HCT). Because HCT often offers the best chance for cure, approximately 70,000 patients worldwide received transplants for hematological malignancies last year. Disease recurrence post HCT is the leading cause of treatment failure. T cells engineered by gene transfer to express a synthetic T cell receptor (TCR) or chimeric antigen receptor (CAR) targeting a tumor-associated antigen have great potential as therapeutic agents, but there is much to learn about how to optimize effectiveness, eliminate toxicities and combine them with HCT. The objectives of this Program Project Grant are to develop effective T cell therapies for patients with the most common indication for allogeneic HCT, acute myeloid leukemia (AML), and autologous HCT, multiple myeloma, and to define the type of graft-versus-host disease (GVHD) prophylaxis that will best allow the use of adoptive T cell therapy post HCT. These objectives will be pursued in three interactive projects. Project 1 will explore the use of specific adoptive immunotherapy using high affinity WT1-specific TCR transduced T cells to treat patients with AML who have failed to achieve an initial complete response with conventional chemotherapy. In addition to determining the toxicity and efficacy of such treatment, this Project will test if cells derived from TN, TCM, of TEBV differ in their behavior, and will address features of TCR T cells and AML that lead to success or failure of treatment. Project 2 will evaluate the safety and efficacy of BCMA specific CAR T cells for treatment of patients with recurrent multiple myeloma. A direct comparison of CAR T cells containing two different co-stimulatory domains, CD28 versus 4-1BB, will be made to determine if they differ in efficacy or toxicity. Further experiments will explore methods to enhance the utility of BCMA CAR T cells including approaches to increase expression of BCMA on target cells or improve the function of CAR T cells by exposure to lenalidomide. In Project 3, two novel approaches to GVHD prophylaxis following peripheral blood HCT (TN cell depletion and post-HCT cyclophosphamide) will be compared to the current standard of care to determine which approach results in the highest percent of GVHD-free, relapse-free survival. Bone marrow and peripheral blood lymphocytes will be evaluated to determine immune reconstitution as well as factors that may best support subsequent adoptive immunotherapy. Success in the pursuit of the goals of this Program Project will provide powerful tools for treating AML and multiple myeloma, and should help define the best approach to GVHD prevention in the era of gene-modified T cells.